A Cold Realization

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A Cold Realization

Susan Solomon, whose research helped answer the riddle of Antarctica's ozone holes, is offering new evidence on a case long considered closed: What killed the 1912 Scott expedition to the South Pole?

The deaths of Captain Robert Falcon Scott and his four comrades have been celebrated as the ultimate in noble striving against insuperable odds – the traditional British take – or as the logical consequence of Scott's hubris and blundering – the more and more prominent revisionist view.

One defense that Scott himself raised in his dying letter to the public, written while he and two colleagues were slowly freezing to death in a tent just 11 miles from a supply cache, was the unseasonable cold.

"I maintain ... that no one in the world would have expected the temperatures ... which we encountered at this time of the year," Scott wrote at the end of March 1912 as the Antarctic autumn deepened to winter.

As evidence, he spoke of temperatures that the team recorded during the previous month – minus 30 degrees Fahrenheit during the day and sometimes as low as minus 47 at night. The cold prevailed despite the party's return to sea level from the plateau 10,000 feet above sea level, where the South Pole lies.

"Our wreck is certainly due to this sudden advent of severe weather," Scott concluded.

Solomon, who works for the National Oceanic and Atmospheric Administration's Aeronomy Laboratory, made observations during her first trip to Antarctica that for the first time linked chlorofluorocarbons to large holes observed in the ozone layer of the southern atmosphere. During her first season in the south in 1986, she stayed at a site just a few hundred yards from a hut Scott used on a 1901-03 expedition.

Her interest in Scott began as a hobby. "I've been to Antarctica four times," Solomon said in a weekend interview. "It's fascinating to read the diaries of the men who were there and to think about what happened to them."

Her interest built enough momentum that she plans to publish a book about the Scott expedition, a volume she says could appear by the end of next year.

Aware of Scott's weather observations, Solomon decided to see whether data from a network of automatic weather stations in the region set up over the past 15 years might give any insight into how severe March 1912 really was.

"It occurred to me that someone ought to take a careful look at the weather data to see whether the weather conditions he experienced were average, easier than average, or tougher than average."

Coincidentally, several stations in the weather network set up by University of Wisconsin meteorologist Charles R. Stearns, co-author of the PNAS Scott paper, are located roughly along Scott's line of march.

This happenstance allows a comparison of the temperatures Scott and company recorded (by twirling an alcohol-filled sling thermometer around their heads each morning) with the temperature record built up since the mid-1980s.

Solomon's conclusion: Scott was dead right in his suggestion that the weather his group encountered as they staggered across the Ross Ice Shelf was worse than they could reasonably have expected. For the final three weeks of the band's struggle back toward safety, temperatures fell to minus 35 Fahrenheit or below every night but one – a good 10 to 20 degrees colder than the weather station data suggest is typical for the area.

For the first five weeks of their journey north, dragging heavy sledges and carrying the knowledge that a Norwegian team led by Roald Amundsen had gotten to 90 degrees south latitude before they had, the weather the party encountered was normal. As they descended from the polar plateau toward the Ross Sea, Solomon notes, one member of the party enthused about basking in temperatures of 10 degrees above zero.

Then the weather changed.

"On February 27, the minimum temperature they measure was minus 37 degrees," Solomon says. "For the next three weeks with one exception the minimum temperatures were below minus 35 every night but one – and one time it was minus 47.... In those three weeks when they really had to hustle, they really had to get home, it turned desperately cold."

Solomon's study is careful to say that the cold is not the sole reason Scott and his companions perished. The principal reason Scott's critics have pointed to was poor planning in the mission's details, including the decision to use Siberian ponies, primitive motorized sledges, and human beings to drag cargo through the snow rather than dogs.

But the cold snap Smith and his crew encountered "turns out to be very unusual," Solomon says. Her study shows that the temperatures the party encountered through February 25 are comparable to the climatological average found in the weather station data.

After that date, the low temperatures were as much as 20 degrees below the long-term average for the region. Solomon also notes that the cold's persistence was unusual, too.

Among the cold's effects were obvious physical tortures such as frostbite and fatigue from lack of sleep and less apparent problems such as changes in the texture of the surface snow that made sledge-pulling more arduous.

"Only one of the 15 years of modern data [1988] displays a nearly uninterrupted period of cold daily minimum similar to 1912," Solomon's study found.